Knife sharpness tester



June 14, 1949. E. w. VARS v 2,472,994

. KNIFE SHARPNESS TESTER Filed Se'pt. 8,1947 r 2 Sheets-Sheet 1 fzo INVENTOR. F: 5 I g am P VA/PS June 14, 1949. E. w. VARS KNIFE SHARPNESS TESTER 2 Sheets-Sheet 2 Filed Sept. 8, 1947 INVENTOR.

' BY 6775A W V/l/iS fl/S ATTORNEY Patented June 14, 1949 is-mp5s: or Bic-E,

" KNIFE :SHARPNESS- TESTER Ethan W; :Vars, Dnncannon, Panassignor,=-.by

-:--mesne assignments; to The Aldonn ProductsH Company, Duncannon,. P2, acorporationlof Pennsylvania'- AppXica-tion'Septemoer 8, 1947;.iSerialiNo2. 712.762

14 filaims.

This invention; reiat'es xtoa knife sharpness testenland more particularly pertains to "one for testingthe sharpn'ess of a'' straight-bladev type of carving or 'slicing ikn-ife; by causing a piece of paper to be di'awn transversely: edgewise= along the :cutting I edge and downwardly thereonto.

The device itests 'the isharpness' of the cutting edge of a knife blade by-causing apieceofpaper to be drawn edgeways along the length-ofthe cutting edge, with a; determined'weight or force, forcingthe-paper downwardly toward said cutting edge,thediathlot-cnt in the paper being a measure of knife sharpnesse The-deviceis -'adjustable'nso' that a standard-condition prevails throughout a series oftests with the same or dif-' ferent knives, whereby-the depth-of A cut produced by a knife-as comparedto the-depth of cut produced byitself'before sharpening, or by another knife takenas-a stahdard7measures the sharpness.

' Therefore it is an-object= of-myinvention to provide means for testing one or -aplurality "of knives, under standard conditions; measuring the sharpness 'by' the depth f but made ina piece of paper presented thereto 'in the-testing operation.

Another object of my invention is to provide 'a knifesharpnesstester devicein-which a piece of paper is drawn transverseiy edgewise along and down onto the-cuttingedgeof' the knife supported for test.

Another object of the invention is .to provide adjustable testing "condition" means 'for such a testing device.

' Further objectsgand' objects relating to details of construction an'd"'economies of operation, will definitely appear 'fromthe detailed description to follow. In'one instance, Irhave accomplished the objects of my invention tbyjthe devices and means set' forth 'in'the following specification. My invention is clearly. defined "and. pointed out in the appended l-claims. A"structure constituting a preferred 'emb'odiment-io'ir'my' invention. is illustrated in the aiccompanying' 'drawings, forming a part 'of this 'specificatiomin' which Fig. 1 is a 'sideelevation' of thedevice'shown in the tilted operative. position, particularly showing. the slide rod and paper .clarnp mounting.

' Fig. 2 is aplanviewof the substance of Fig. 1.-

Fig. 31s a sectional .view of vpart lof .the .substance offigl; on the .line 3 -3 thereof.

Fig. 4 is a. sectionaltview. takenpn the. line 4-4 of Fig.1.

Fig. 5 is.. a sectional ..view on-the-line .5-5 of Fig. v-1, with.epartsshi ;enaway.- and showing-a piece ofnape'r held insthe clampe- I2 I Fig. -6 1 is a section. throughthe. paper clamp, on the line 65of Fig.2.

Fig. 7 is a perspective view of .the device at the beginning of anpoperation with the paper in contactwith-therean-endmf theecutting edge of the knife.

In the drawings thB-aSGGtiOHELLViBWS .are taken on'the gsectionwlines.looking. in the direction of the arrows.

Reierringto the -=drawing-s,: I provide a base platform 20,- upright support.posts. 2| .and. 22, spacedapar-t at opposite endsaof-thelplatform, and having supported therebet-ween. aeslide rod' 23, and beneathit a .stop. supporting slide rod 24 on which are mounted-stops 25 :and1 26,- adjustably positioned lengthwise thereon-and held by means of set screws 21-- and-28 respectively.

A-slidable mountinglag has a.tubular aperture 30 through which-slide rod 23 passes, so that said=*-mounting i29, -unless otherwise rest-rained, mayslideonr0d23between posts 2| and 22. Depending from slidablesmounting '29 :is a fork 3! whichstraddles the .stopsliderod-Zd, and the adjustedpositions ofestops -zdand 26, between which the fork is positioned; to determine the limits between which the slidablemounting can move along rod 23.

' Projecting-upwardlyirom mounting 29, is a bearing portionfi32 *(Fig fi) having atubular aper ture =33, whose" axis is-transverse to the 'rod- 23 and substantially r'horizontal; -saidaperture 33 rotatably receivingazsh'aft 34 which has secured to :one endxth'ereof ian L-shaperil support 35 (Fig. 2 fromwhich :extendsa rod: :36, threaded on its outer 'end, to receiver a counterweight 31 adjustably screwed-thereon; Extending in. the other direction from .the -L-shapedi support 35;- is a balance-rod 538;,having slidably mounted thereon a balance weight:==-3,9, which may {be slidably adjusted .011. the balance-mod :38 andwsecured thereto by means vofa:setsscrew w.As. wil1:-be:1ater explained', r the a counterweight 23,7 est-normally 'set to balancetrotating forcesrac-ting on'ishaft' 34, to prevent its rotating; :andtheiadiustment of balance Weight 39? mayibe'rmadegalongzthe scale 4|, inscribed on balance rod 38,.to'iprovidevan' ad justedturning-force foristfaft iim J Secured to :the: :other.iendaioiishaft "S t-is paper clamp holding' yokie r42 :(Fig; :6 having zzbent-over ears-:43iand Mfithroughrwhichruns. a hinge pin .45." 'Hingedizontpinffi,zbetween. the" ears 43 and 44" of: yoke '42 :ris :an. innerxtpaper; ,zclamp plate 46 having"bent-ovewfianges .41: and- 48 "pierced to receive pin w: and: an outer paper clamp; plate 49 having-wbentfi-over rhanees .50 and- 5 I; through which pin 45 passes. The clamping plates 46 and 49, at the hinged ends thereof, are spaced slightly apart, but extend outwardly and toward each other to end in a curved beak portion 52 (Figs. and 7). A piece of paper, such as strip paper commonly used in adding machines, may be inserted between the plates 46 and 43, when they are separated, and when the plates are moved together the extending portion of the paper will be positioned as is portion 53 (Fig. 7).

To facilitate insertion and removal of paper strips from the paper clamp, and to secure them in place after insertion, I provide on plate 49, ears 54 and 55 (Fig. 5) through which a. pin 56 is passed, the upper end of said pin 58 terminating in a handle 51. Mounted on the upper end of pin 55 by a collar 58 is a cam'59 having a cam slot til (Fig. 2) in which rides a pin 5| which passes through the flanges ll and 48 of the inner paper clamp plate 46, extending therebeneath to pass through a similar slot in a cam 65 (Fig. 5) also secured by a collar 63 to pin 56. Suitable apertures are provided in flanges 50 and 5! of outer clamp plate 49 to accommodate the pin 5! when the plates are in closed position as shown in Fig. 2. To open the plates, to receive paper, the handle of pin 56 is turned, turning pin 56 and cams 59 and 52 in a counterclockwise direction as seen in Fig. 2, forcing the plates apart so that paper may be inserted through the beak 52, which is then opened. The handle 51 is then turned in the opposite direction to close the paper clamp. On each operation of the testing device, the paper clamp is opened and the strip of paper is pulled outward slightly to present a new portion thereof for test purposes.

The weight of the paper clamp, tending to rock shaft 34, is counterbalanced by adjustment of counterweight 31' on rod 35, with balance weight 39 in the position shown in Fig. 1. To provide a weight-bias, tending to cause the paper-holding beak end of the paper clamp to move downwardly with a calculated force, the balance weight 39 is moved along the scale to a point where such weight-bias is had and it is then clamped in I place by set screw 49.

It will be perceived that, if the slide is moved toward the stop 26, by means of handle ill (Fig. 1), and the left end of the platform, as seen in Fig. l is elevated, as therein shown, the slide 29 will move down along rod 23 until the fork 3! stops against stop 25. If the paper clamp has been rocked upwardly by the operator, before the sliding motion occurs, the paper clamp will have both a rectilinear sliding motion and a rocking motion, downward, with a force selected by the adjustment of the balance weight.

To provide the proper tilting of the platform base 29, which preferably, should be approximately I provide a yoke-like leg or brace H hinged to the platform as at 12 and 13, which leg is held, releasably secured, by a bead chain M in the position shown in Fig. '7 by means of hook 72a. Between operations, the chain M may be released and the platform allowed to assume a horizontal position.

Referring especially to Figs. 4 and '7, I provide a knife support comprising a supporting post 85 secured to base 2i by means of screw bolt 8|, said post being hollow and receiving the pin 82 of an anvil 83 provided with an arm 84 through which passes an adjusting screw 85 to position a clamp member 86 toward and away from the face 81 of said anvil 83, whereby a knife blade 88 may be clamped therebetween, cutting edge upward, and

Gil

extending outwardly from said anvil in a plane parallel to the plane of slide of the paper clamp. Set screw 89 provided in post cooperates with neck portion 90 of pin 82, so the anvil, and consequently the direction of alignment of blade 88, may be adjusted around the vertical axis to make the knife blade axis extend in the direction of slide movement of the paper-holding equipment, so there will be no cross-sliding action of the paper relative to the cutting edge of the knife. The extended knife blade may be pointed upward slightly, if desired, as shown in Fig. '7, to attain a greater relative cutting action of the knife blade through the paper as the sliding motion occurs.

It will be apparent, from looking at Fig. 7, that, as the paper clamp slides lengthwise with respect to the knife blade and also rocks downwardly, the projecting portion 53 of the paper strip, is caused to move in transverse edgewise relationship along the length of the cutting edge of the knife and is forced downwardly thereonto, the depth of cut of the knife into the paper being a measure of the sharpness of the knife. By testing a series of knives under the same balanced weight-bias condition, the relative sharpness of them may be secured or by testing a knife during various stages of sharpening its improvement may be noted.

The fact that the curved beak 52 holds the projecting portion 53 of the paper supported along the direction of cut in the paper, a uniform cutting resistance in the paper is secured.

In operation, the platform base is adjusted to the tilting angle by means of the yoke-like brace H and the knife to be tested is secured in the knife clamp against the anvil 83 by means of the set screw 85, and the position of the knife around the vertical axis is adjusted by means of set screw 89. The paper clamp is then opened and a piece of paper is inserted between the plates of the clamp and the clamp is then closed, leaving projecting from the beak a portion of the paper. The balance weight 39 is then adjusted to the selected place on the scale, the operator holds the slide against the stop 26, at the same time rocking the paper clamp to the position shown in Fig. '1, whereupon the operator releases the paper clamp and the sliding and rocking movement thereof causes the knife blade cutting edge 90 to out edgewise up into the protruding end of the paper to a depth determined by the sharpness of the knife. As the paper moves along the knife edge, the rocking down of the paper clamp will not take place until the knife cuts the paper. The arrows on the perspective view of the device (Fig. 7), show the direction of movement of the elements as the operation of testing proceeds.

I am aware that the machine described and illustrated herein may be varied considerably without departing from the spirit of my invention, and, therefore, I claim my invention broadly, as indicated by the appended claims.

Having thus described my invention, what I claim as new and useful and desire to secure by Letters Patent is:

1. In a knife sharpness tester, in combination, a platform base; means attached to the base which is adjustable to till; it from a normal horizontal position so that one end is raised; a slide rod supported by the base and extending above and along it in lengthwise direction; a knife support mounted on said base for holding a knife blade, cutting edge up, extending alongside the slide rod; a mounting slidably mounted on 'the slide rod so that when positioned near the up rag a-994 55 ward-senator.- :the :rod; whenzitiltedtit' toward'itheulower end; aspaperiiclamp,ireckably edge, whereby; when" the base; is tlit'emthe -p aper clamp rocked .upwardlyrsdtherlower tedgecof the paperwlies above and aim-085 513118 a cutting-sedge "of the knife; andthe mounting andepaper clamp are slidlby an operator-mo theaupperzend ofrthe' rod and released, the :combined; sliding .and rocking movement, :given the paper; causes athe paper to move :in': edgewise1cutting-srelation downwardly and along .tthe I length of=:the--b1ade,ws ;the@ depth -of the cut-inthe paper being-aimeasurezofi the sharpness of. the/cutting edgesof the-blade.-

2; In a knife sharpness tester, inrcomblnations a plat-formbase; means-: attaehed--*to the base which is adjustable totiltit? froma-.=normal horizontalposition: so that r one end: is: raised; a slide rod supported by v the base. and extending above and along it in lengthwise: directionr-a" knife support mounted: on said base for holding a knife blade, cutting edge up, extendingg-alo'n'gcrthe.slide rod; amounting slidably mounted-bathe slide rodso'that when positionednear then-upward end of therod, when:ti1ted-,-,itwill slide toward the-lower end; an upperstopand alower stop, mountedonrthe'platformbase, between which the slidablemounting may move; a apaper .-clamp rockably mounted in the slidable x-mounting so as to rock around a-horizontal-taxis:normal to the slide' "rod,- said .clampbeing adapted: to hold a piece-ofpaper edgeways across-rzthec vertical plane inwhich the supported; knife :blade lies,

said paper I clamp being weightsbiased so :as .to tend to rock the held paper downwardly across the knife blade cutting edge; wherebyg=when the base is tilted, theipaper clamp rocked upwardly so the lower edge of the paper lies above and across the cuttingedgeof the-knife, and the mounting and paper clamp are -slidaby-an operator to the upper end of the--rod- -and-released, the combined sliding and rocking movement given the papenca-uses the paper to movein edgewise cuttingrelation downwardlyi and along the length oftheblade, the depth of cut in'rthe paper bein a measureof the sharpness iof.-s=the cuttingedge of the blade.

- 3. The-device of claim 2 in. which the weightbias of the :paper clamp compriseszan adjustable counterweight, adjustment of which determines the force with whichthe' paperisrocked downwardlyonto the knife cuttingedge.

'4, The device of claim 1 irrrwhich the weightbias of the paper clamp comprises an adjustable counterweight, adjustment of which determines the force with which the paper is rocked downwardly onto the knife cutting edge.

5. The device of claim 1 in which the paper clamp consists of two fiat plates hinged at one end together, the other ends of said plates being curved into a beak, and in which the paper is held between said plates and extending outwardly from said beak.

6. A knife sharpness tester, including, in combination, knife support means for holding a knife blade extended, cutting edge up; paper-holding means pivotably mounted on a slidable supporting means mounted alongside the knife support means, said paper-holding means holding a piece ofzzpaper edgeways across :thevplanezoffsthe knife 1' blade, and weight-biasing means 'actingzuponfthe paper-holding means so that? when: :the :paper holdingz means slides, the 1 held :paper;;is:imoved edgeways downwardly andalong "thetiknifelcuta ting-edge.

'7.- A knife :sharpness tester,"v including,.ini combination, knife support means :for holding 'a knife blade-extended, cutting edgeup; rockable paperholding" means slidably mounted alongside the knife support means, said paper-holding means holding apiece of paper edgeways across l't-h'e plane ofthe knife blade, andweight-biased means forx rocking the paper-holding means soi'th'at' when the paper holding means slides and recks; the held paper-is moved edgeways downwardly and along the knife cutting edge.

J -8. A' knife sharpness tester, including, in combination, a base; a knife holder secured to thebase, said holder being adapted to receiveand hold a knife with its blade extending outwardly therefrom, edge up; a paper clamp pivotably mounted on a slidable membersecured to' 'the base, said clamp being adapted to hold a 'strip' ofpaper so it extends in a plane 'crossing t-h'e plane of the knife blade and. weight-'biasedmeans for turning the paper clamp so that sliding-movementof the paper clamp causes 'the' 'paper to move along the length of the blade sothe 'kn'ife ed'gewill make edge-cutting contact with' the paper-as the paper moves along the lerigth' 'of the blade edge.-

9.- A-knife sharpness tester, including, incombination, a base; a knife holder secured-*tothe base, said holder being adapted to ree'eiveand hold a knife with its blade extending outwardly therefrom, edge up; a slide mounted on the base substantially parallel to the blade of a-held knife; amounting slidably mounted on the slide; a paper clamp-reckably mounted on a horizontal'shaft rotatable in the mounting, and means for yielda-bly rocking the paper clamp, said paper'clamp being adapted to hold a strip of paperso when the clamp is rocked the paper extends edgeways across and above the knife edge, said slide and said rockable mounting being so located,' 'with respect to the knife blade held in the knife holder; that the sliding movement of the mounting carrying' the paper clamp and thedownward rocking movement of the clamp, causes the paper tomove downwardly toward and along the length ;of i the blade-sothe knife edge will make edge cutting contact with the paper as the paper moves along the length of the blade edge, the rockable mount! ing of the paper holder being biased to rockdow'm wardly.

"10. In aknife sharpness tester, in' combination, a" base; a support for holding a knife with'lthe blade extended andthe cutting edge pointed upwardly, and said knife support being secured to said base; a paper clamp slidably mounted on a slide member secured to the base and provided with two plates forming a beak portion gripping the paper, said clamp being rockable upwardly and downwardly in its mounting and being adapted to hold a strip of paper so when it is rocked upwardly the paper extends edgeways across and above the knife edge, so that sliding movement of the paper clamp causes the paper to move along the length of the blade so the knife edge will make edge-cutting contact with the paper, as the paper moves along the length of the blades edge, and so that rocking downward thereof causes a cutting of the blade into the 7 paper, said clamp supporting said paper in the beak portion close to the line of cut.

11. A knife sharpness tester, including, in combination, a platform base; a slide rod mounted on and extending between standards which extend upwardly from the base; a mounting slidably mounted on the slide rod, between limits; 3. paper clamp rockably carried by the mounting so the clamp will rock on a horizontal axis transverse of the slide rod, said paper clamp being weight-biased by means associated therewith to rock downwardly around the axis when first rocked up; a knife holder for holding a knife with the blade cutting edge upward and extending therefrom parallel to the slide rod, said elements being so positioned with respect to each other that a piece of paper carried by the clamp, when the clamp is rocked upwardly, extends edgeways across and above the knife edge when the mounting is slid to its limit at one end of h the slide rod, so that sliding movement of the mounting to the other end of the slide rod will carry the paper held in the clamp along the knife edgeways, and so the weight-bias of the paper clamp will, during such sliding motion, cause the paper to move into slicing contact with the knife blade cutting edge, along its length.

12. A knife sharpness tester, including, in combination, a platform base; a slide rod mounted on and extending between standards which extend upwardly from the base; a mounting slidably mounted on the slide rod; limiting means defining the length of the sliding movement of the mounting on the rod; a paper clamp rockably carried by the mounting so the clamp will rock up and down on a horizontal axis transverse of the slide rod, said paper clamp being weightbiased by means associated with the clamp so as to rock downwardly around the axis when, first, it has been rocked upwardly; a knife holder for holding a knife with the blade cutting edge upward and extending therefrom parallel to the slide rod, said elements being so positioned with respect to each other that a piece of paper carried by the clamp, when the clamp is rocked upwardly, extends edgeways across and above the knife edge when the mounting is slid to its limit at one end of the slide rod, so that sliding movement of the mounting to the other limit on the slide rod will carry the paper held in the clamp along the knife edge, edgeways, and so the weightbias of the paper clamp will, during such sliding motion, cause the paper to move into slicing contact with the knife blade cutting edge, along its length.

13. A knife sharpness tester, including, in combination, a platform base; a slide rod mounted on and extending between standards which extend upwardly from the base; a mounting slidably mounted on the slide rod; limiting means defining the limits of motion of the mounting on the slide rod; a paper clamp rockably carried by the mounting so the clamp will rock up and down around a horizontal axis transverse of the slide rod, said paper clamp being biased so as to rock downwardly around the axis; a weight-biased means for holding the paper clamp, a knife holder for holding a knife with the blade cutting edge upward and extending therefrom, parallel to the slide rod, said elements being so positioned with respect to each other that a piece of paper carried by the clamp, when the clamp is rocked upwardly, extends edgeways across and above the knife edge, when the mounting is slid to its limit at one end of the slide rod, so that sliding movement of the mounting, caused by elevation of that end of the platform from which the sliding movement is to be made, causes the mounting to slide to the other limit on the slide rod so as to carry the paper held in the clamp along the knife blade cutting edge, edgeways, and so the paper clamp will, by its downward rocking, during such sliding movement, cause the paper to move into slicing contact with the knife blade cutting edge along its length, the depth of out made in the paper being indicative of the sharpness of the knife.

14. A knife sharpness tester, including, in combination, a knife support means for holding a knife blade, cutting edge up, a paper-holding means mounted on a rotatable shaft alongside the knife support means in position to hold a piece of paper edgeways across the plane of the knife blade, :1 weight-biased means holding the paper against the knife blade and means for permitting relative movement, longitudinally of the knife edge, between the paper-holding means and the knife support means so that the paper is moved edgewise downwardly on the knife cutting edge as the knife support and paper-holding means move relatively.

ETHAN W. VARS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,619,305 Norris Mar. 1, 1927 2,008,678 Brown July 23, 1935 2,285,371 Strauss June 2, 1942 2,335,235 Clifton Nov. 30, 1943 2,340,401 Martin Feb. 1, 1944 FOREIGN PA'I'ENTS Number Country Date 610,077 Germany Mar. 1, 1935 

